It's called like an egg to an egg, whenesto hen inaye can have a variety of colours, shapes and sizes. This from Grandma's malso egg yolks "somehow yellower than the stores" and the neighbor's behind the fence seem bigger. But it's not just a first glance, eggs can also differ in tom, what's under shell - in its composition.
The Czech golden-spotted hen and the oravka hen are Czech and Slovak national breeds that have been bred and raised for centuries. And it is these two breeds that scientists have chosen for their research. They compared how breed, housing and age of the hen can affect the quality of the eggs laid. For example, they were interested in the weight and shape of the egg, the strength and colour of the shell, the ratio of yolk to white, but also blood parameters such as total cholesterol and blood protein levels.
The researchers evaluated eggs from 34, 42 and 50-week-old hens reared in the so-called "hen house". enriched cages and those from bedding farms. A total of 132 animals were used in the study and 60 eggs were collected from each breed during the study period. In addition, blood samples were also taken from the laying hens themselves. The hens were sampled between seven and eight o'clock in the morning from the wing vein.
And what did the results show? Significant differences were found, for example, in the amount of cholesterol in the blood, which was higher in hens reared in enriched cages. Differences in total protein content again were age-related laying hens, the younger ones had a higher proportion in the blood. In terms of egg quality, shell colour was mainly influenced by breed, while housing system influenced weight, surface, thickness and shell strength. The results obtained present an interesting comparison of changes in blood biochemical parameters and egg quality. These factors certainly need to be further investigated, especially in other breeds where such data are unfortunately often lacking for the time being.
The original work can be found here:
www.sciencedirect.com/science/article/pii/S0032579120307926
Kraus, A., Zita, L., Krunt, O., Härtlová, H., & Chmelíková, E. (2021). Determination of selected biochemical parameters in blood serum and egg quality of Czech and Slovak native hens depending on the housing system and hen age. Poultry Science, 100(2), 1142-1153.
